Tooth for crushing-rolls.



e TED ST TE ATENT OFFICE. V

JOHN s. JoHNso or LANsFoRii; PEN sYLvANIA, ssIGNoa or ONE-FOURTH TO GEORGE w. WILMOT, or HAZLETON, PENNSYLVANIA, AND ONE-FOURTHYTO SAMUEL v. TENCH, or ILANSFQRD, rE'NNs LvAN troorrirron oRUsHING-RoLLsQ Specification of Letters Patent. i Patented Sept. 8, 1914.

Application filed September 4, 1913. Serial No. 788,066.

To all whom it may concern Be it .known that I, JOHN S. JOHNSON, citizen ofthe United States, and a resident of Lansford, county of Carbon, State of Pennsylvania, haveinvented a certain new and useful Improvement in Teeth for Crushing-Rolls, of which the following is a specification.

My invention relates to an improvement in teeth for crushing, grinding or breaking machinery and more particularly to the teeth for rolls usedin coal breaking and crushing rolls, though it will be obvious that the invention is not limited to the specific material mentioned, but is equally adapted for use in stone'and material of like nature.

In crushing mechanism it lias-been the practice heretofore to employ pointed teeth having a plurality of sides with substantially plane surfaces andintermcdiate corners forming cutting edges and constituting a body th transverse section of which is rectangular or polygonal in shape. It has been found however that teeth so formed-have inherent disadvantages which seriously impair the efficiency of the crushing apparatus and limit the production of material. I 1

In my previous lnventionl have (IGVlSQClEL tooth structure wherein the disadvantages of a tooth rectangular or square in transverse section have been obviated and it is the object of my invention to provide a tooth wherein the sides bounding the cutting edges materially assist the cutting action of such edges instead of hindering and retarding the same, all as will be pointed out hereinafter.

It further consists of other novel features of construction as also will be fully set forth hereinafter.

In the drawings,-l igure 1 is a perspective view of a breaking or crushing tooth embodying my invention; Fig. 2 is a view in side elevation of the same; and, Fig. 3 is a front end view of the tooth.

Referring to the drawingsl designates the shank of my novel cutting and crushing tooth, which is adapted to seat in the cylinder of a crushing or breaking roll for coal,

of any metal suitable for the for cutting,

I are either fixedtpermanently or are remova ably secured.so that the removal and replacing of a tooth for any purpose are convemently accomplished.

The teeth embodying my invention are preferably of steel but of course they may be purpose.

In my present invention I have designed the teethfor use either as a fixed part of the roll or as an element removable therefrom and in the preferred embodiment the latter use is'contemplated more than the former since that is the more prevalent practice at the present time.

It will of course be understood that the teeth may be secured in any well known or desired manner to the rolls as this forms two parts of my present invention.

The shankl carries a body portion comprising a plurality of sides 2 converging and tapering from the base 3 to a common point 4:, while they adjacent sides meet in the respective edges 5 .which formthe cutters crushing or breaking the material. These cutting edgeso ag will be noted are preferably curved from thebase 3 to the point 4 having substantially the same contour asthe sides 2, it being noted that the said edges 5 and sides 2 give to the body portion a shape closely approximately a cone.

The material of the body portion between the several sides 2 is cut away to form concave grooves 6 which extend longitudinally of the body portion, and form a plurality of pockets bounding the said body, the function of which pockets will now be explained by a brief reference to the prior art. In cutters or teeth heretofore in use it has been the practice to provide the body portions of the teeth with plane sides so that in trans-- verse cross section the body is rectangular or polygonal in form. Such a construction affords in practice an opportunity for the coal, stone or the like to slide along the plane surface which either results in too large pieces or the material being forced against the cutting edges with consequent dulling or breaking of the edges, or in causing an initial wedging which prevents the same from being properly fed to the crushing point. Such construction of teeth also resulted in the reduction of a wasteful percentag of the coal into a crumbled and powdered form in which the particles move too fine for certain uses. I

By my present novel construction I have obviated the foregoing disadvantages by providing the aforesaid grooves or pockets 6 into which the material or a part thereof seats during the feeding action and thereafter as the teeth are rotated an initial crushing action takes place which places the material in condition for final disintegration when subjected to the action of the edges 5. Furthermore it will be seen that by giving the grooves 6 a concave form there is practically no opportunity for the material to ride on the surface of the body portion as the force from the tooth during the rotary movement is applied substantially concentric to the path of the rotation. Attention is also directed to the fact that theaforesaid novel construction provides a plurality of relatively sharp cutting edges the sides of which are comparatively narrow and whereby the regrinding of the several' cutting edges is greatly facilitated and the repair and replacement of the tooth members may be made in a minimum of time,'all of which is highly desirable in this type of mechanism.

I am aware that it has heretofore been proposed in the patent to Clark No. 174,719 March lath, 1876, and in the patent to Richmond 216,807 June With, 187 9, to employ crushing rolls provided with teeth, each having converging sides and of rectangular cross section.

It is desirable in the commercial manufacture and practical use of devices of this character that the part be simple, strong and constructed to give the longest service and highest efficiency without constant attention and wider manipulation, and it is the purpose of my invention to accomplish these results.

My present invention is clearly differentiated from the Clark and Richmond devices aforesaid, as will be apparent to those skilled in the art, since the same comprises a body portion having a plurality of concave sides adapted to effectually prevent the material from wedging against the teeth adjacentto their cutting edges.

It will now be apparent that I have devised a novel and useful construction of teeth which embodies the features of advantage enumerated as desirable in the statement of the invention and the above description and which I have in the present instance shown and described the preferred embodiment thereof which has been found in practice to give satisfactory and reliable results, it is to be understood that the same is susceptible of modification in various particulars without departing from the spirit or scope of the invention or sacrificing any of its advantages.

I claim 1. As a new article of manufacture, a tooth for a crushing roll comprising a body portion having converging, tapering and concaved sides, the edges between adjacent sides constituting cutting edges.

2. As a new article of manufacture, a tooth for a crushing roll having concaved, converging and tapering sides and also having longitudinally curved cutting edges intermediate adjacent sides. a

3. As a new article of manufacture, a'

tooth for a crushing roll comprising a pyramidal body portion having concaved side surfaces and also having longitudinally curved cutting edges intermediate the said sides.

4:. As a new article of manufacture, a tooth for a crushing roll comprising ashank and a body portion having converging, ta-' pering sides, which sides are concaved whereby longitudinally curved cutting edges are formed intermediate adjacent sides.

In testimony that I claim the foregoing as my invention, I have hereunto signed my name this 27th day of August, A. D. 1913.

JOHN S. JOHNSON.

"In the presence of G. W. IVILMoT, A. V. TENOH.

Copies of this patent may be obtained for five cents each, by' addres'sing the Commissioner of Iatents,

Washington, D. C. 

